POS0124 SURVIVAL ANALYSIS IN CONNECTIVE TISSUE DISEASES WITH INTERSTITIAL LUNG DISEASE COMPARED TO IDIOPATHIC PULMONARY FIBROSIS: MULTICENTRE ITALIAN STUDY
Authors: M. Fornaro, F. Cacciapaglia, M. Giotta, G. Zanframundo, M. G. Lazzaroni, A. Bartoletti, E. Pedretti, G. Sambataro, M. Orlandi, C. C. De Pace, S. Colella, D. Lacedonia, C. Vanchieri, P. Airo’, L. Cavagna, S. Guiducci, F. Iannone
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Interstitial lung disease (ILD) is a major cause of mortality in patients with connective tissue diseases (CTDs). Previous studies have shown a worse survival in patients with idiopathic pulmonary fibrosis (IPF) (1-2), however, these studies were mainly focused on patients with rheumatoid arthritis, whereas few data are available for patients with other CTDs. <h3>Objectives</h3> The aim of this study was to assess the 5-year survival in an Italian multicenter cohort of ILD patients suffering from systemic sclerosis (SSc), dermatomyositis (DM), and anti-synthetase syndrome (ASS) compared to IPF patients. <h3>Methods</h3> Demographic and clinical data of patients with SSc, DM and ASS were retrospectively recorded from January 2015 for the purpose of this study. The baseline time was a diagnosis of ILD confirmed by computed tomography (CT) scan of the chest. The IPF cohort was used as control group. Progressive lung disease was defined when the patient presented within 24 months after the diagnosis of ILD with at least one of these characteristics: a) a relative decline in FVC of at least 10% of expected value; b) a relative decline in FVC from 5% to less than 10% of the expected value and a worsening of respiratory symptoms or an increase in the extent of lung fibrosis on high-resolution CT scan; c) a worsening of respiratory symptoms and an increase in the extent of lung fibrosis on high resolution CT scan. All data were reported and analyzed with standard descriptive statistics, as appropriate. The 5-year survival was assessed with the Kaplan-Meyer method; univariate and multivariate Cox-regression models were built to look for possible risk factors. Data were analyzed with SAS/STAT Statistics version 9.4 (SAS Institute, Cary, NC, USA). <h3>Results</h3> The overall cohort included 177 CTD-ILD patients (99 SSc, 25 DM, 53 ASS) and 153 IPF patients. At ILD diagnosis, as expected, CTD patients were younger [median age (IQR); IPF: 68 (63-73) years, SSc 58 (46-66) years, DM 54 (51-65) years and ASS: 59 (60-67) years; p &lt;0.001 vs IPF] and predominantly female (IPF: 23%, SSc 83.5%, DM 81% and ASS 65%; p &lt;0.001 vs IPF). Usual interstitial pneumonia was observed in a low number of CTD patients, evidenced in 11 (11.5%) SSc, 7 (12.9%) ASS and 4 (16.6%) DM patients. At ILD diagnosis, the median (IQR) value of forced vital capacity (FVC%) was similar between IPF [75%(64-91)], DM [79%(60-90)] and ASS [77.5%(64-93)], while was significantly higher in SSc patients [94%(79-106), p&lt;0.001 vs IPF]. At baseline, all CTDs showed a higher mean (SD) value of diffusing capacity for carbon monoxide (DLCO%) [SSc: 63%(18), DM: 62%(23), ASS: 63%(22)] than IPF [50%(15); p&lt;0.001]. During follow-up, 10 (9.7%) patients with SSc, 4 (16%) with DM and 3 (8%) with ASS showed a progressive subset of ILD. CTDs showed better 5-year survival compared to IPF (log rank: p&lt;0.0001) (Figure 1). Multivariate Cox analysis highlighted that male gender (HR: 2.29, 95% CI 1.25-4.18), age at diagnosis (HR: 1.07, 95% CI 1.04-1.10) and DLCO at baseline (HR: 0.95, 95% CI 0.94-0.97) were independent prognostic factors in CTD-ILD. <h3>Conclusion</h3> The prognosis of CTD patients with lung fibrosis appears to be significantly better than those with IPF. The early detection of lung involvement in at-risk patients like SSc, DM and ASS, and the availability of effective immunosuppressive treatment may explain this discrepancy. Of note male patients, older age and compromised DLCO at baseline represent poor prognostic factors. <h3>References</h3> [1]Navaratnam V, Ali N, Smith CJ, et al. Does the presence of connective tissue disease modify survival in patients with pulmonary fibrosis? Respir Med. 2011 Dec;105(12):1925-30. [2]Kim EJ, Elicker BM, Maldonado F, et al. Usual interstitial pneumonia in rheumatoid arthritis-associated interstitial lung disease. Eur Respir J. 2010 Jun;35(6):1322-8. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.